1. Field of the Invention
This invention relates generally to the art of connecting data terminal equipment (DTE) users to remote computer systems (or hosts) through a wireless or radio wave data communication network. More particularly, the present invention relates to the remote control of a gateway in a wireless communication network.
2. Description of the Related Art
Over the past several decades, various communication networks have evolved to meet the growing need for access to information. Among the more familiar types of systems used for communication are wire-based telephone communication systems that use physical wires or optical fiber links to connect users. Data transmission using wire-based telephone communication systems can be accomplished using existing AT Modem technology. An AT Modem is a standard data communication equipment (DCE) connection device used with telephone equipment for converting or modulating an asynchronous stream of data into a phone line carrier signal. The connection between an AT Modem and a DTE, such as a personal computer or a portable computer, is usually through an RS-232 interface. One of the principal disadvantages of a wire-based telephone communication network is that users are limited to specific locations where wired connections are available. Another disadvantage is that wire-based telephone communication networks usually require dedicated telephone lines, which can be expensive.
Recently wireless data communication networks have emerged that enable information exchange by sending and receiving data through high frequency radio signals. Examples of such networks include the Mobitex Radio Network (Mobitex), which is operated by RAM Mobile Data, and Ardis, which is a joint venture of Motorola and IBM. Mobitex was developed in Sweden by Ericsson/Eritel and has been installed and is maintained in many other countries. For example, in Canada, Mobitex is operated by Roger's Cantel. Making efficient use of these wireless data communication networks to connect DTE users to remote computer systems is one of the objects of this invention.
Electronic data communication is organized into networks that have established protocols and specifications. Communication between computers takes place over a connection that is established using a common protocol. A data communication network generally refers to a collection or grouping of computers organized for co-operative communication of data. Once a connection is established, there are a number of data transfer methods used by various data communication networks. Both Mobitex and Ardis use packet switched data transfer methods, which aggregate data into blocks called packets before it is transmitted.
Ericsson also manufactures a device called a Mobidem, that is a radio-based modem capable of transmitting digital information across the Mobitex data communication network. Communication between Mobitex and data communication networks or just a single personal computer is now possible.
Many problems can arise when a wireless network, like Mobitex, attempts to supply connections to existing networks and computers. For discussion purposes, the example of linking Mobitex to an X.25 network or a computer supporting the X.25 protocol will be used throughout the specification, though it is to be understood that the present invention can be configured for other protocols.
The linking of Mobitex to an X.25 network creates several problems including the following:
(a) Timing errors cause many standard data transfer protocols to fail. The tremendous speed difference between the slow running Mobitex and a very fast X.25 is the main cause of such failures. PA1 (b) Because of the timing errors many potential customers' needs are not met, which in turn mattes the product difficult to sell. PA1 (c) The sizes of information packets can vary between two networks resulting an underutilization of packet space and reducing communication performance. PA1 (d) A DTE is limited to using only one session at a time when connecting into Mobitex using the Mobidem-AT, an AT Modem device. PA1 (e) No standard method exists for updating address changes for mobile units bridged to networks or other computer systems. Also, no standard method exists for addressing remote systems through a gateway for an access point.
Using a particular protocol, a gateway bridges the gap between the connecting parties. The objective of the present invention is to provide a gateway product with enhanced speed, performance, and compatibility when bridging different networks. By providing a fast and efficient gateway connection, in accordance with the present invention a flexibility in communications with mobile users is achieved and the problems outlines above are, in large measure, solved.